Automatic control for gas making machines



Jan. 10, 1956 R. B. COOMBE AUTOMATIC CONTROL FOR GAS MAKING MACHINES Filed April 7, 1951 2 Sheets-Sheet l IN V EN TOR. JZJmwza fi. C 0 0222 $6 BY I o Qays'.

Jan. 10, 1956 R. B. COOMBE 2,730,437

AUTOMATIC CONTROL FOR GAS MAKING MACHINES Filed April 7, 1951 2 Sheets-Sheet 2 PYROMETER RELAY THERMOCOUPLE 4 7 INVENTOR.

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United States Patent AUTOMATIC CONTROL FOR GAS MAKING MACHINES Raymond B. Coombe, Oak Park, Ill.

Application April 7, 1951, Serial No. 219,864

8 Claims. (CI. 48-74) My invention relates generally to the generation of gas especially from petroleum or like liquid hydrocarbons and more particularly with a new and improved method and means for controlling the operation of a conventional oil gas or water gas generating machine.

In the familiar commercial production of gas, for use in the household, from a suitable grade of petroleum, such as diesel or low grade fuel oil etc., it is the customary practice to gasify or crack the oil within intermittently heated checker chambers in a conventional gas making machine. The checker chambers normally are heated during a heat phase of the gasification cycle by first burning oil therein until the internal temperatures of the chambers reach a desired and satisfactory cracking zone or thermal level for the particular type of make oil being used. Make oil or process oil is then introduced to the heated checker chambers during the make phase of the gasification cycle with the heat stored therein during the heat phase serving to gasify or crack the make oil until the chamber temperatures drop below the cracking zone temperature limits for that particular oil, thus ending the make phase. The heat and make phases are again repeated in that order during succeeding gasification cycles. Such a gas making process may be termed a batch type" characterized by the heat phase persisting until the desired checker chamber temperatures are gained with the make phase lasting until the checker chamber temperature falls below the cracking zone for the make oil being. used. It will be recognized that a normal consequence of this process is the absence of successivegasification cycles of consistent and uniform time duration because of well recognized external and internal thermal factors which serve to vary the rate of heat absorption and dissipation in a conventional gas makingmachine.

From the above described process the manufacturer, of course, gains a primary product of fuel gas suitable for household. use. In addition certain by-products are produced of which tar is probably the foremost; the by-prodnets of this process often serving to defray the cost of It is Well. recognized in the gas. making industry that by this. above described process it is very difficult to obtain a uniform gas product since the temperature of, the checker chamber fails to remain constant during the make phase of. the gasification cycle. In general it may be stated that oil which. is heated to a very high. temperature tends to crack into high. volatile gas products and tar. or pitch by-products; the gas having a. relatively large volume and a low heating value. or B.t.u-. rating, Conversely, oil cracked and gasified at relatively lower temperatures produces low volume, high B. t. u. gas with lighter by-product-s, such as kerosene and fuel oil.

It is also recognized that during the above described process both high and low B. t. u. gases. are. produced be.- cause of the fluctuation of temperature. within. the checker chambers.

In recent years. the public. utilities or gas making industries, which supply the consumers with household gas, have turned more and more to the supply of natural gas found in large abundance in the southwestern section of the United States. This natural gas is carried into the utility storage facilities through large pipe lines. Because of the difiiculty of storing a large enough quantity of this natural gas to meet all conditions of demand, the utilities have made it a general practice to augment their natural gas supply during the high peak or demand periods of the days operation with process or oil gas made generally in accordance with the method outlined above.

It immediately will be appreciated that this use of oil gas as a standby medium involves certain demands in the quality of the product produced by the gas making machines; the foremost consideration of which is probably that of a uniform gas having the necessary calorific content and readily mixable with the natural gas so as to supply the consumer with a uniform combustible product of an acceptable quality. It also will be recognized that during the peak load demand periods, the supply of augmenting oil gas must be constantly available as desired; the rate of demand or quantity of oil gas required varying as the peak load requirements vary. However, since the conventional batch type of gas making process, as outlined above, produces gas only intermittently during the make phase of the gasification cycle, a constant supply of oil gas is usually insured with the conventional gas making machine by utilizing more than one such machine, the several machines being operated instep or alternate synchronized relation.

With the use of more than one gas making machine, however, I have found that it is desirable, for maintaining alternate or synchronized operation of the several machines, to have the time of the cycles of the several machines constant and of uniform length to avoid overlapping of their operation which is detrimental to ethcient gas plant operation. This latter is especially important when several such machines deliver their gas products to a common outgoing pipe line which of necessity is limited to volumetric capacity; such being a usual set up employed in many utility gas plants in the United States today.

It will thus be appreciated that in order to meet the desirable constant cyclic operation of the conventional oil gas making machines, while maintainingv a standard quality of the gas produced, a basic alteration of its cyclic operation, especially as to the method of control is essential.

Briefly, I propose to gain a constant cycle operation for a conventional oil gas making machine by regulating automatically the internal temperature of the checker chambers thereof through varying the supply of make oil introduced thereto during the make phase of the gasification cycle; the determination of the rate of make oil supply being correlated to a pyrometricindication of the checker chambers internal temperature, with. the total results. of my proposed control means being to approach a desired constant chamber temperature during the make phase to bring. about an etficient and improved gasification cycle of. a given and predetermined duration which is maintained constant. for repeated or successive cycles of each gas making machine.

One of the main objects of my invention is to disclose a new and improved means for controlling the operation of a conventional oil gas making machine whereby constant cyclic operation thereof is possible.

Another important object of' my invention is to disclose a new and improved means for controlling. automatically the internal checker chamber temperatures of a gas making machine during the make phase of its cycle by changing the supply rate for the process or make oil at a given pyrometrically determined stage of the make phase cycle.

Another object of my invention is to demonstrate a new and improved method of controlling an oil gas making machine whereby the gasified product therefrom will approach a standard calorific quality and the tar by-prodacts of the process will likewise be of a controlled quality.

Still a further object of my invention is to demonstrate a new constant cycle mode of operating a conventional oil gas making machine wherein the supply of heating oil introduced thereto during the heat phase of the operational cycle is maintained at a constant rate for successive gasification cycles, with the heat phases each being of a constant and uniform duration and the quantity of make oil supplied thereto during the make phase of its opera tional cycle varied as determined by a pyrometric indication of the machines checker chamber temperature.

The above and further objects and features of my invention will be recognized by one familiar with the gas making art from the following descriptive materials and with reference to the accompanying drawings.

In the drawings:

Figure l is a schematic representation in front elevation of a vertical type of conventional gas making machine (portions thereof being shown in cross-section) provided with the control features of my invention; and

Figure 2 is an enlarged schematic representation illustrating the details of my automatic control system for varying the supply of make oil to the gas making machine, illustrated in Figure 1 of the drawings, in accordance with the teachings of my invention.

Referring specifically now to Figure l .of the drawings, it will be observed that I have schematically illustrated therein a vertical style of gas making machine which one cognizant of the oil gas making art will recognize as being very similar to a conventional Williamson, single shell carburetered blue gas generating machine; such being included herein as an illustrative type of machine to which my control means is especially adapted. It will be recognized that this vertical Williamson type of gas making machine comprises essentially three main chambers of which the lowermost is a generator with one upper vertical chamber 11 being a carbureter and a second upper vertical chamber 12 being a superheater. An interconnecting hydrogen pipe 13 communicates with one side of the generator chamber 10 and the upper end of the carbureter chamber 11. As herein illustrated, protective checkers 14 are installed above the normal grate work 15 positioned in the lower section of the generator chamber 10 so that primary air may pass through the checkers during the heat phase of the gasification cycle after emission from an air supply line connection 16; such emission being regulated by a suitable control valve 17 located in the supply line. The air from supply line 16 fiows upwardly through the protective checkers 14 and A combines in combustion with heat oil sprayed from a conventional burner nozzle 18 located within the generator slightly above the protective checkers therein. After combustion of the heat oil, the products of combustion flow along the refractory walls of the generator and pass upwardly therefrom through the outside flue pipe or hydrogen pipe 13 which leads to a vertical connecting section 19 thereof communicating with the top of the carbureter chamber 11. Normally, in operation, an excess of air is passed upwardly through the generator and the products of combustion together therewith serve uniformly to heat the checkerwork of the carburetor cham ber 11 as well as checkers in the superheater chamber 12. From the carbureter the products of combustion and air pass downwardly into the lower end of the superheater 12 via an opening 21 formed in a common separating wall 22 positioned between the carbureter and superheater. During this heating phase a stack valve 23 located at the upper end of the superheater chamber 11 is maintained in an open condition thereby to permit the passage of the heated gases and air upwardly into the outgoing stack 24 located directly above the superheater chamber 12.

Near the end of the heating phase, the machine is purged in a conventional manner with steam or air either by opening an auxiliary air supply valve 25, located near the upper end of the carbureter 11 in addition to the primary air supply valve 17, or a steam valve 26 leading into the bottom of the generator via a suitable conduit 27 may be opened as desired. After a short purge period, stack valve 23 is closed and steam from conduit 27, as permitted by the opening of the valve 26 therein, sweeps upwardly through the generator absorbing heat therefrom to enter the carbureter 11 through the top thereof as before with the heating gases. Shortly thereafter (approximately 5 seconds) make oil spray 30, located at the top of the carbureter, sprays make or process oil into the upper section of the carbureter chamber covering the heated checkcrworks in the carbureter chamber with a fine mist of make oil which results in gasifying the oil as it contacts the checkerworks. Upon the opening of the make oil spray 30 the steam sweeps the oil gases, formed from the cracking of the make oil fuel, downwardly through the carbureter 11 and upwardly through the superheater 12 where it is then passed laterally outward through a side wall of the superheater via a gas offtake conduit 31. The gas otftake conduit discharges into a usual wash box 32 and leaves the same through an outlet connection 33 in a conventional manner.

it will be observed that the cubage of the carbureter. exclusive of the checkers therein, is approximately equal to the like measured cubage of the generator chamber. It also should be noted that even though the gas making machine normally is operated in a cyclic manner with steam being used in the gas making phase to carry and displace the fuel gas generated, substantially no other gas is formed during the operation except for a small amount of blow gas. Such carbon as is uniformly deposited on the checkers during the gas making phase is rapidly and completely burned off during the initial portion of the following heat phase without the production of local hot spots.

In order to adapt the gas making machine, such as the Williamson type illustrated, to an operational or gasification cycle having a constant duration, such being adverse to its normal operating characteristics, I utilize a new and improved means of controlling the make oil supply during the make phase of the cyclic operation of the gas making machine. As will be recognized from Figures 1 and 2 of the drawings, the physical aspects of my control apparatus includes a make or process oil supply line in which a master hydraulic cutofl? valve 41 is established with the supply line 41) being divided into two branches 42 and 43 immediately after the cutoff valve; the two branches later joining to a common make oil fuel line 44 in which is mounted a conventional oil flow meter 45 for measuring the quantity of oil as it flows into the top of the carbureter and out of the oil spray 39. Controlling the flow of oil through the first branch 42 of the main oil supply line 40 is a reverse acting diaphragm valve indicated generally at 46. The second or by-pass branch 43 of the main oil supply line is similarly provided with a manually operable by-pass valve 47. It will thus be observed that if both the diaphragm and by-pass valves are opened simultaneously a greater quantity of oil is allowed to pass into the make oil line 44 and thence to the carbureter than if one of the branch lines 42 or 43 thereof is isolated by the closure of its associated valve 46 or 47. Under my method of control I propose automatically to actuate the reverse acting diaphragm valve in response to a pyrometric determination of a given control temperature existing within the checker chamber of the superheater thereby accordingly changing the rate of supplying make oil to the machine in response to depression of the internal temperature of the checker chambcrs to a preselected control temperature. In order to accomplish the automatic. actuation of diaphragm valve 46, as clearly will. be seen in Figure 2 of the drawings, I have connected a source of high pressure. air by supply line 50 to the upper side of the diaphragm 51 of valve 46. This air supply line 50v is provided with a pressure regulating device or regulator52' isolated by suitable cutoff valves 53 and 54, an air pressure indicating gage 55 and' an electrically actuated solenoid: valve 56. It should be recognized that the air supply line 50 is open to the atmosphere immediately after the solenoid valve.- 56. The solenoid valve is electrically actuated to open and close the high pressure air supply line; such being associated in electrical circuit with a conventional pyrometric indicator shown generally at 6.0-. A thermocouple 61, adapted to be mounted within the interior of the superheater or carbureter as desired at. a given control position such as illustrated in Figure 1, is. associated in a conventional way with the pyrometer; such serving, by thermally induced E. M. F., to indicate, in a known manner, the internal temperature of the. superheater. The pyrometer includes suitable micro-switches (not shown) associated in circuit with an electrical relay 62. When a predetermined selected control temperature is reached within the superheater and electrically relayed from the thermocouple to the pyrometer, the micro-switches. are closed, energizing the relay 62 which in turn serves to electrically actuate the solenoid valve 56 opening the high pressure air supply line 50 to permit the pressurized air. from that line to' exhaust to the atmosphere. This venting action serves to relieve the downward pressure on diaphragm 51 associated with control valve 46; The. diaphragm valve, being a reverse acting valve, then closes and the oil flow rate to nozzle 30 is reduced to'a lower constant rate; the make oil then passing solely throughthe. secondor by-pass branch line 43 instead of through. both the branch lines 42 and 43'. Additionally if for any reason the machine heats up again during a given makephase to a point above the control temperature then the pyrometer will open the circuit permitting the solenoid valve 56 to close and thus permit pressurized air to open control valve 46 resulting in an increase in the make oil flow rate again, thereby cooling the machine. It will then. be recognized that the higher feed rate will be maintained by thepyrometrictcontrol system so long'as the machine maintains temperatures above the control temperature and conversely the lower feed rate will be maintained for machine temperature below the control temperature. Themast'er; cut'voif valve 41 is conventionally operated from a control panel (not shown), and may be closed at the end of a. given desired and predetermined time interval to: stop the; make. phase by cutting off all supply of. make oil.

To more fully understand the purposes; of; operating and controlling the make oil rate of. supply as outlined above, it is necessary to understand that I contemplate controlling the internal temperature of the: gas making machine during the make phaseof its cyclicoperation by' varying the make oil input thereto. In this' latter connection it is well recognized in the gas making art that the introduction of oil to a gas making: machine of the type. de scribed herein serves normally to cool the checkers thereof and consequently lower the internal temperature of the machine. Furthermore it willberealized. readily" that the introduction of make oil to the. carbureter at a higher rate-will. serve to lower the internal temperature of the gas making apparatus faster than ifmake oil is fed thereto in smaller quantities or at a lower rate of: flow. Bearing these principles in mind, I therefore propose to introduce make oil to the carbureter at an initial constant high rate of flow immediately after the: termination of the heat phase of the gasification cycle when the internaltemperature of the carbureter and superheater. are at their higher levels. Subsequently, after the internal. temperature of the. checker chambers have. been lowered to a givenpredetermined control temperature, I propose to. reduce the rate. of make oil. fiow to the carbureter to. a secondconout the. entire make phase.

stant. flowrate so as to cause a, resultant reduction in, the rate of internal cooling of the gas making apparatus. From a study of the drawings it will be recognized that with the diagraphm valve 46 and by-pass valve 47 open make oil will be. sprayed into the carbureter of the gas making apparatus at a given. fixed rate of flow and that with the diaphragm valve 46 closed, oil will continue to flow into the carbureter through the by-pass branch line, but at a lower fixed rate of flow. In this connection it especially should be remembered that both feed rates of flow for the make oil are constant and that no throttling occurs during the duration of the individual given rates of flow thereof.

It is further recognized, by those familiar with the art of gasifying petroleum, that. for a given oil or petroleum suitable for cracking into gas and heavier hydrocarbon by-products, there exists a given reference temperature or cracking zone temperature at which the best gasifying results will occur. Therefore, if the temperature within the carbureter and superheater of a gasmaking apparatus, as described above, could be maintained at the reference temperature for a particular make oil during the entire phase of its gasification cycle, very favorable gas making conditions would prevail. However, because of the fact that heat is added to the checker works of the carbureter and superheater only intermittently in the batch style of machine herein described, that is during the heat phase, so that. there is only a given quantity of total heat available for cracking the process or make oil for each make phase, it will be appreciated that as more and more make oil is introduced into the carbureter and superheater there is a natural tendency for the internal. temperature of. the apparatus to decrease with the rate of heat dissipation from the checker chambers varying generally in accordance with the. rate of feeding the make or process oil thereto. This latter feature, of course, results in. a gradual lowering of the internal temperature of. the checker chambers as the make phase of the gasification cycle proceeds. It. will be appreciated, of course,.that' if at the end of the make phase the internal temperature of the carbureter and superheater is below' that necessary for the gasification of the make oil, little or no cracking and gasification will occur. It is therefore a recognized practice in the operation of this type of. gas making apparatus to terminate the make phase prior to the lowering of the internal temperature of the checker chambers to a temperature below that of the cracking temperature zone limits for the particular make oil being gasified. Following this operational practice, the make phase is: conventionally terminated whenever the lower cracking limit temperature is reached; such resulting in make phases of unequal duration which, as explained above, are undesirable where synchronized cyclic operation of. several gasmaking machines is involved. In order to decrease the rate at which the internal temperature of the carbureter and superheater is lowered during the make. phase of the gasification cycle and thus maintain the internal temperature of these chambers at a more uniform level throughout the make phase, I have found that convenient control thereof may be accomplished by initially introducing make oil to these chambers. at a rate in excess. of that which would serve. to give satisfactory gasification and cracking of the petroleum ifthe internal temperature of the. carbureter and superheater were maintained at a given reference cracking, temperature through- I then maintain this excessive makeoil feed rate during the initial stages of the make phaseuntil a predetermined pyrometrically indicated control temperature is reached within the carbureter and superheater. Following this initial excessive make oil rate of feed, I then diminish the make oil feed rate so that the rate of flow into the carbureter is below the requirement of the remaining. heat or temperature within the chambers. for satisfactory gasification at the reference cracking temperature. with the oil involved. It will be appreciated. that. by this; method of oil feed control I alleviate the danger of burning out the checker works and overheating of the apparatus which is often times prevalent at the start of the make phaseythe feeding of the make oil thereto at a rate in excess of the reference temperature rate requirements serving rapidly to cool the machine and maintain the temperature within a safe range. versely, during the later stages of the make phase wherein the make oil is fed to the carburetor and superheater at a rate below that which is necessary for satisfactory gasification, at the reference temperature, the latent heat of the checker works serves to heat the face of the c eckcrs and in many instances may actually raise the internal temperature of the machine. It is singular to note that by the use of these two predetermined flow rates their combined effect is substantially equivalent to maintaining the make oil feed rate at a constant level which ould bring about satisfactory cracking and gasitication of the oil it the internal temperature of the machine were tained at the substantially constant desired cracking reference temperature during the entire make phase of the cycle. In other words I have found that by varying the rate of feeding make oil to the apparatus during the make cycle, first at a rate in excess of the constant reference cracking temperature requirements of the apparatus and Com then at a rate below the constant reference cracking temperature requirements that the total quantity of oil cracked during a make phase of a fixed duration is substantially equivalent to that amount of oil which would have been cracked if the temperature Within the checker chambers were maintained at a predetermined cracking temperature throughout the make phase and the oil fed thereto at a given constant rate, such being the theoretically most favorable cracking condition.

By way of illustration, consider a typical gasification cycle in accordance with my above teachings. For convenience consider the total length of the gasification cycle to be approximately four minutes with the heat phase be ing fixed at two minutes duration and the make phase of a two minute duration. During the heat phase, and during each successive heat phase of successive gasification cycles, heat oil is introduced to the machine at a constant rate so that a constant quantity of oil is added to the machine and burned therein, such resulting in the addition thereto of a constant quantity of heat. For example, assume 1,000,000 B. t. u. is added to the machine by the heat oil feed rate for two minutes during each heat phase. After the burning of the constant quantity of heat oil the machine is purged as described heretofore and the make phase is commenced. Now, assume, for illustration, that the addition of the 1,000,000 B. t. u. to the machine during the heat phase serves to raise the internal temperature of the checker chambers to 1600" F. Further assume that the make oil may be gasified within the temperature range of 1600-1400" F. and 1500 F. is the theoretical reference cracking temperature giving the best gasifying results for the make oil used so that if such temperature were maintained for the entire make phase and make oil fed thereto at a given rate, theoretically optimum gasification conditions would prevail. Suppose, for example, that a reference feed rate of 100 gallons a minute is the rate at which the reference temperature of 1500 F. would gasify the make oil with the most satisfactory results if such ref erence temperature were maintained during the entire en suing two minute make cycle. In accordance with my invention, I propose to feed make oil to the machine during the initial stages of the make cycle at an excessive or overload rate with respect to the reference temperature and rate requirements. This initial rate may for example be substantially 10% greater than the reference rate, or in keeping with'the illustrative figures, at 110 gallons per minute. It will be recognized that the 110 gallon rate will permit acceptable gasification of the oil so long as the temperature of the apparatus is maintained above the reference temperature of 1500 F. I have found in actual op eration that a 10% excess initial feed rate of the make oil over the reference rate is satisfactory in most normal conditions for gasifying petroleum in a gas maker by my control means. As this excess rate persists, the temperattire of the machine normally will lover from the 1600 F. temperature toward the 1400 F. lower cracking range limit with the gas produced during this initial stage being of a high volatile low B. t. u. content.

Suppose further that at the end of one minutes duration of the make phase, the checker chamber temperature, as pyrometrically determined, has reached the reference temperature of 1500 F. which would mean that the 110 gallon rate would be greatly in excess of the reference rate of 100 gallons per minute required by that reference temperature to bring about the best gasification results. In such an instance the control temperature would be approximately 1500 F. as well and the pyrometer would be set to actuate the control valve at that temperature so as to alter the make oil feed rate by closing the diaphragm actuated valve 46 to stop oil flow through the first branch line 42 thereby cutting the rate of feed to a level approximately 10% below that required by the 1500 F. reference temperature or say to gallons per minute. The internal temperature of the machine then being 1500 P. will again permit satisfactory gasification of the oil during the remaining one minute period of the make phase as before; the gas being produced during this stage having a high B. t. u. content and low volume. Because of the fact that during the second stage of the make phase, oil being fed to the machine at a rate less than that which the available heat therein would cause the most desirable gasification, there is a tendency of the checker works to give off latent heat which helps to maintain the temperature within the machine at a nearly contant level and in some cases may actually serve to increase the machines temperature. It will be recognized from these illustrative figures that by first using the 10% overload or a 110 gallon rate during the first minute of the make phase and the 10% underload feed rate, or 90 gallon rate, during the second minute of the make phase I have approximated the conditions which would persist if the temperature of the machine were maintained at the 1500 F. reference level for two minutes and oil was fed thereto at the gallon per minute reference rate.

Thus it will be appreciated that the total theoretical effect of my process and method of operation is equivalent to that of operating with a constant time make cycle at a constant make oil feed rate and at a constant temperature. It further should be recognized, in connection with the make phase operation of my gasification cycle, that if for some reason during the initial stages of the make phase, wherein the oil is fed to the machine at a rate in excess of the reference rate and temperature, the temperature of the machine continues to rise or for some reason fails to fall below the predetermined pyrometric control temperature, then the initial high rate might persist for the entire two minute period of the make cycle; this rate also persisting during successive make cycles until the reference temperature is reached during some successive make phase. This condition is by no way detrimental to the gas maker since greater quantities of efiiciently produced gas would be gained thereby. However, it would be a rare instance where the excessive rate would be continually sustained during successive make phases of the cyclic operation of the gas making machines; external temperatures factors, the natural cooling effect of the excessive make oil rate and other factors intervening to lower thc temperature of the gas making apparatus. It also should be recognized that since the time for changing from the higher to the lower rate of feeding the make oil to the machine during the make phase is determined by a single pyrometric determination of the internal temperature of the checker chambers, and as such the control temperature is not always reached at the same time of each cycle, the total quantity of oil gasified during successive make phases may not always be the same and in practice is usually not identical.

This may be more understandable if is recognized that if the machine, during the make phase, retains a temperature in excess of the control te mperature for the particular oil being used then the higher rate will persist for a longer period of time and may even persist during the entire two minute make phase. Conversely, the initial 10% overload feed rate may persist only a short period of time during the initial stages of the. make phase, say for instance onehalf. minute period before the pyrometric reading indicates the control temperature has. been reached and causes automatically the alteration of the rate of feed to the 10% underload rate, so that the total quantity of oil gasified during. each make phase is entirely dependent upon the length of time during which the two separate rates of feed are maintained.

Although in the above illustration the control. point of changing the feed rates was set forth as occurring at the endv of one minute of a two minute make phase, such is not necessarily always the case (although in actual practice I have found that the control point of rate change usually occurs somewhere close to the midpoint of the make phase time). To determine the control temperature or point in the make phase. at which the make oil feed rates are changed from the high to the. low rate so that the pyrometer may be, set for automatic actuation of the diaphragm valve as described above, several factors are taken into consideration among which are the B. t. u. content of the gas being produced and the grade of tar or by-product ensuing from the gasification of the petroleum. An analysis of these items as to density, heat content, volatility, the tars viscosity etc., is accomplished by known means well recognized by those familiar with this art and the pyrornetric control is then set to actuate the control valve at a temperature designed to bring about a desired product. Thus, if a 500 B. tu. gas were. desired, such under my process being the admixture of high volume, low B. t. u. gas made during the initial stages of the gas making phase and low volume, high B..t. u. gas made during the latter stages of the gas making phase, the pyrometric control temperature would be set initially at a position dictated by past operational experience so that the admixture of these two types of gas produced during the make phase would result in a gas of the desired quality. By way of illustration, if during the initial stages of the make phase when the 10% overload feed rate is utilized, a gas having a 250 B. t. u. content is produced and during the latter stages of the make phase when the 10% underload feed rate is used, a gas having a 750 B. t. u. content is produced; the control temperature would be set on pyrometer to bring about an expected admixed gas having an average 500 B. t. u. content. If after the completion of the gasification. cycle, the operator finds the gas made thereby to be ofa B. t. u. content in excess of that desired, the pyrometer control temperature is adjusted so that the time of the initial stages of the fixed time make phase (or that stage in which the excessive feed rate is utilized) is lengthened and the time of the latter part of the make phase is correspondingly shortened thereby to lower the B. t. u. content of the resultant admixed gases and vice versa. Conversely, in-many operations, especially where a restrictive piping problem is involved for taking away the by-producttar or'the like, the content of the tar may become the governing factor and its ability to flow readily may" determine the control temperature at which the change of make oil feed rate should occur since by regulating the type of gas made, that is either a high B. t. u. or low B. t. u. content gas the resultant admixed tar or by-products are correspondingly regulated as to quality so that their viscosity may be adjusted similar to the gas quality adjustments as above.

Briefly, the underlying theory behind my process or mode of control is based upon the recognized theorum that for a given or total quantity of heat available for cracking a given petroleum thereexists av given. quantity of that petroleum whichetfectively may be gasified thereby at a given effective cracking temperature and time. Since, for reasons recognized by those familiar with the gas making art, it is most difficult to maintain the temperature of the checker chambers at a constant level during the make phase of the conventional gas making machines operation and assure that succeeding heat phases will bring the temperature of the checker chambers to a given cracking temperature without varying the length of time of the heat or make phases, I propose to accomplish such an operation by adding a given quantity of oil or heat to the gas making machine during each successive heat phase and to gasify make oil during each make phase by first feeding thereto make oil in quantities in excess of that Which a predetermined reference cracking temperature for that particular oil would require for desired gasification. I then automatically lower the make oil feed rate, during the latter stages of the make phases, to a second constant rate which is less than that required for desired gasification by said reference temperature. By averaging the two rates of feed during the make phase in eifect my method of control approximates that which is most desirable wherein the temperature of the checker chambers is kept at a constant level during the entire make phase and oil is fed thereto at a constant rate so that the total available heat gasifies a given quantity of oil during a fixed period of time.

Thus it may be observed that I have provided a new and improved modeof operating a conventional oil gas or Water gas generating apparatus and have illustrated suitable physical means whereby such gas generating apparatus may be controlled and operated in accordance with my invention. It will be recognized and appreciated that while. I have described my mode of control as related to an oil gas making machine its principles apply equally as well to a carbureted water gas making machine as well and that by the heretofore described mode of operation it is possible to operate an oil or water gas making apparatus with a gasification cycle of a fixed duration so that several such machines readily may be adapted for synchronized operation with ease and improved effectiveness as desired.

While I have herein illustrated and described one form of control media. by which the method. of operation as taught by the features of my invention may be accomplished, it readily will be recognized that numerous changes, modifications, and substitutions of equivalents may be made therein without departingfrom the spirit and scope thereof. Therefore, I do not wish to be limited to the specific features of the control means illustrated except as may appear in the following appended claims.

I claim:

1. In the production of gas and condensible byproducts from petroleum in a gas. making machine having intermittently heated checkerwork chambers, the improved mode of maintaining successive. gasification cycles of said machine at like constant time duration, comprising the successive steps of, adding a given quantity of heat to said machine during a fixed time heat phase of said cycle, said heat serving to preheat. said checkerwork chambers to within a preselected cracking temperature range for a given type of make oil to be gasified, introducing said make oil into said preheated checkerwork chambers at a given first rate of. flow, maintaining said first rate of flow constant until the internal temperatures of said checkerwork chamber falls toa given predetermined value within said cracking temperature range, and then reducing said flow rate abruptly to a second constant and diminished rate of flow for the remainder of the make phase for said fixed time makev phase.

2. In the production of gas and condensible byproducts from petroleum in a gas making machine of the type employing intermittently heated checkerwork chambers, the improved mode of maintaining successive gasification cycles of said machine at like constant time duration, comprising the successive: steps. of, adding a given quantity of heat to said machine during said cycles heat phase, said heat phase being fixed at a constant time duration for each gasification cycle and for successive cycles of said machine, said heat so introduced to said machine during said heat phase serving to preheat said checkerwork chambers to Within a preselected cracking temperature range as determined for the particular type of make oil to be gasified, introducing make oil into said preheated checkerwork chambers at a given first constant rate of flow, said first rate of flow being maintained until the internal temperature of said checkerwork chambers falls to a given predetermined value lying within said cracking temperature range, then reducing said flow rate immediately to a second constant and diminished rate of flow with said second rate of flow enduring for the remainder of said gasification cycles make phase, the latter being of a constant time duration for each gasification cycle and for successive gasification cycles of said machine.

3. In the production of gas from petroleum in a gas making machine of the type utilizing intermittently heated checkerwork chambers, the improved mode of controlling the cyclic operation of such a machine to bring about successive gasification cycles of constant and uniform duration, comprising the successive steps of, adding given constant quantity of heat to said machine during successive heat phases of successive gasification cycles, each of said heat phases being of uniform constant time duration, introducing make oil to said checkerwork chambers, which have been preheated during said heat phases to a temperature within a predetermined cracking temperature range for said make oil, at an initial constant high rate of fiow which serves to cool said chambers to a predetermined control temperature within said cracking temperature range, determining by pyrometric indication when such control temperature has been reached, and then reducing said make oil rate of flow immediately to a second and diminished rate of flow and maintaining said second rate of flow so long as the temperature of said chambers remains at or below said control temperature; the combined duration of said two constant rates of flow being maintained at a constant fixed time interval which is uniform for successive gasification cycles of said machine.

4. in the method of manufacturing gas and byproducts from petroleum in intermittently heated checkerwork chambers, the improved mode of controlling the gasification cycle and internal temperature of said checkerwork chambers to bring about a constant time duration for said cycle, comprising the successive steps of, combustibly introducing heating petroleum to said checkerwork chambers at a constant rate and for a constant time interval representing the heat phase of said cycle, the products of combustion of said heating petroleum serving to heat said :heckcrwork chambers to a temperature in excess of a desired cracking reference temperature. for the particular type of make oil to be gasified, introducing make oil to said heated checkerwork chambers for gasification therein at an initial constant flow rate in excess of a predeteriined constant reference flow rate required for satisfactory gasification of said petroleum at said reference temperature if such reference rate and temperature were maintained constant throughout a constant make phase time, diminishing said make oil flow rate to a second constant flow rate below said reference fiow rate at a predetermined temperature of a checkerwork chamber as indicated by a single pyrometric determination of the internal temperature of said checkerwork chamber, and maintaining said second rate of flow for the remainder of said make phase.

5. In a control system for regulating the supply of make oil to a gas making machine for producing gas from petroleum introduced to intermittently heated checkerwork chambers therein, the combination comprising, a make oil supply line for feeding make oil to spray means located within the interior of said machine, said make oil supply line being separated into a first branch and a bypass branch which commonly feed into said spray means, a by-pass valve in said by-pass branch, a diaphragm actuated control valve in said first branch, a high pressure air line connected with a source of compressed air at one end and venting to the atmosphere at its other end, said air line connecting to said control valve and supplying pressurized air to the upper side of an actuating diaphragm thereof for opening said control valve, an electric solenoid valve in said air line between its connection with said diaphragm control valve and its venting outlet, a thermocouple positioned within the interior of said machine, a pyrometer associated in circuit with said thermocouple for indicating internal temperatures of said machine in conjunction therewith, and electrical circuit means associating said pyrometer, thermocouple and said solenoid valve for automatic actuation of said solenoid valve whereby the latter will be opened to permit the venting of air from said air line in response to a pyrometric indication of a preselected internal temperature of said machine, said opening actuation of said solenoid valve serving to cause closure of said first branch by said diaphragm control valve thereby altering the rate of flow from said make oil supply line to said spray means.

6. A control system for adjusting the rate of feeding make oil to a gas making machine of the class described, comprising, a make oil supply line, a diaphragm actuated control valve in said supply lines, a by-pass line communicating with said supply line and circumventing said control valve therein, a thermocouple located in a selected control zone within said machine, a conduit means carrying pressurized fluid to one side of the diaphragm in said control valve, an electrical solenoid valve means in said conduit, means electrically connecting said solenoid valve with said thermocouple for operating the former in response to a preselected electromotive output of said thermocouple; operation of said solenoid valve to an open position causing responsive operation of said control valve thereby to alter the rate of feeding make oil to said gas making machine.

7. In a control system for regulating the delivery of make oil to a gas making machine of the class described, the combination comprising, a make oil supply line divided into a main branch and a by-pass branch, diaphragm actuated shut-01f control valve means in said main branch, pressurized fluid control means arranged to activate said control valve means, a spray means commonly fed by both said supply line and branches, thermocouple means disposed at a selected control point within the gas making machine, pyrometric means responsive to the electromotive output of said thermocouple, and means electrically relating said pyrometric means, thermocouple and fluid control means for operating said control valve means, the arrangement being such that the supply of make oil to said spray is coursed alternatively through said main branch and said main branch and by-pass branches to effect alternate fixed feed rates to said spray means depending on the opening and closing of said control valve in response to the occurrence of preselected thermal activity within said machine.

8. A control system for adjusting the rate of feeding make oil to a gas making machine of the class described, comprising, a make oil supply line, a diaphragm actuated control valve in said supply line, a by-pass line communieating with said supply line and circumventing said control valve therein, a thermocouple located in a selected control zone within said machine, a conduit means carrying pressurized fluid to one side of the diaphragm in said control valve, an electrical solenoid valve means in said conduit, means electrically connecting said solenoid valve means with said thermocouple for operating the former in response to preselected electromotive output of the latter; said control valve being normally open such that the opening of said solenoid valve serves to vent said conduit 3 determined by the carrying capacity of said by-pass line.

References Cited in the file of this patent UNITED STATES PATENTS Evans Oct. 20, 1931 Jones Oct. 20, 1931 14 Cabell Dec. 1, 1931 Cabell Jan. 19, 1932 Andrews May 30, 1933 Hulf et a1 Feb. 20, 1934 Stirling Jan. 12, 1937 Winkler et a1 Oct. 18, 1938 Hall Oct. 8, 1940 

5. IN A CONTROL SYSTEM FOR REGULATING THE SUPPLY OF MAKE OIL TO A GAS MAKING MACHINE FOR PRODUCING GAS FROM PETROLEUM INTRODUCED TO INTERMITTENTLY HEATED CHECKERWORK CHAMBERS THEREIN, THE COMBINATION COMPRISING, A MAKE OIL SUPPLY LINE FOR FEEDING MAKE OIL SPRAY MEANS LOCATEDS WITHIN THE INTERIOR OF SAID MACHINE, SAID MAKE OIL SUPPLY LINE BEING SEPARATED INTO FIRST BRANCH AND A BYPASS BRANCH WHICH COMMONLY FEED INTO SAID SPRAY MEANS, A BY-PASS VALVE IN SAID BY-PASS BRANCH, A DIAPHRAGM ACTUATED CONTROL VALVE IN SAID FIRST BRANCH, A HIGH PRESSURE AIR LINE CONNECTED WITH A SOURCE OF COMPRESSED AIR AT ONE END AND VENTING TO THE ATMOSPHERE AT ITS OTHER END, SAID AIR LINE CONNECTING TO SAID CONTROL VALVE AND SUPPLYING PRESSURIZED AIR TO THE UPPER SIDE OF AN ACTUATING DIAPHRAGM THEREOF FOR OPENING SAID CONTROL VALVE AN ELECTRIC SOLENOID VALVE IN SAID AIR LINE BETWEN ITS CONNECTION WITH 